Device for holding and setting jointer knives



Sept. 13, 1949. M. A. LORD DEVICE FOR HOLDING AND SETTING JOIN'I'ER KNIVES Filed May 16, 1947 2 5 N0 1 W NA .1 z/ f M W% m w a o H E, 0 sw 2, M a: /2 a u. H w 5 Z 6 3 33 u g 2 a v a 4 w v Patented Sept. 13, 1949 OFFEE DEVICE FOR HOLDING AND SETTING JOINTER KNIVES Maxwell A. Lord, Denver, Colo. Application May 16, 1947, Serial No. 748,432

1 Claim. (Cl. 51-218) This invention relates to a device for use in sharpening and setting jointer knives. It is exceedingly difficult with ordinary equipment to obtain the proper bevel and a perfectly straight edge on a jointer knife and without straight edges the knives cannot operate efiiciently. V

The principal object of this invention is to produce a compact, easily used and highly emcient device which will enable an unskilled operator to obtain a perfect bevel and perfectly straight edge upon a jointer knife in a conventional drill press.

It is also exceedingly difficult to set the knives in a jointer head in absolute alignment with the rear jointer table and unless the knives are so set they cannot of course produce eflicient work.

Another object of this invention is to so construct the device that it will enable anyone to set the knives in a jointer head so that every knife and every portion of the edge of every knife will travel in a perfect cylindrical plane about the axis of the head in tangential alignment with the rear table of the jointer. A further object of the invention is to so construct the device that it may be used on jointer knives of various lengths and widths and of various thicknesses and types without change in the device.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efficiency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

Fig. 1 is a fragmentary longitudinal section through a conventional jointer illustrating a side view of the invention as it would appear in use thereon:

Fig. 2 is a perspective view of the improved device for sharpening and setting jointer knives;

Fig. 3 is a cross section through the device, taken on the line 3-3. Fig. 2, illustrating it as it would appear placed in a conventional drill press for sharpening purposes;

Fig. 4 is a detail vertical section through a knife setting plunger employed in the improved device; and.

Fig. 5 is a cross section taken on the line 5-5 Fig. 2.

In Fig. 1 typical portions of a conventional jointer are designated by numeral as follows: front table II]; rear table II; jointer shaft l2; jointer head It; jointer knife l4; jointer knife clamping block I5; and jointer knife clamp screws l6.

In Fig. 3 portions of a conventional drill press arranged for grinding and sharpening the knives M with the use of theimproved device-are designated by numeral as follows: 'drill'chuck ll; cupped grinding wheel [8 and work table H3.

The improved sharpening and setting device comprises an elongated frame block 20 terminating at each extremity in clamping feet 2| and 22, each provided with an attachment bolt slot 23. An inclined surface 24 is formed along the front of the frame block 20. The incline of this surface 24 corresponds to the incline of the bevel of a conventional jointer knife. A longitudinally extending locating groove 25 is formed along the bottom of the inclined surface 24 and a'projecting ledge portion 26 extends "outwardly from the groove 25. i I

A clamping bar 2'! rests against the ledge portion' 26 and is provided with a longitudinally extending flange 28 which rests'in the bottom of the groove 25. The clamping bar 21 is for the purpose of clamping one of the knives l4 against the inclined surface 24. The clamping is accomplished by means of clamp screws 29 the heads of which bear against the bar 2'! and the shanks of which are threaded on an incline into the frame block 26.

The blade to be sharpened rests upon projecting screw extremities 30 formed on blade adjusting screws 3|. The screws 3| are threaded on an incline through the ledge portion 26 in the plane of the blade l4 and the extremities 30 extend through notches in the flange 28 so as to contact the back edge of the blade. The screws 3| are adjusted to bring the sharp edge of the knife M to a perfect level. The clamp screws 29 are then tightened to clamp the knife M in the adjusted position.

The sharpening is accomplished by placing the frame block 20 upon the drill press work table l9 below the grinding wheel l8 as shown in Fig. 3. The frame block 20 may be bolted to the table is by means of suitable attachment bolts through the slots 23 if desired. The drill press is adjusted to hold the grinding wheel l8 in a pre-set Vertical position. The table I9 is then swung back and forth beneath the grinding wheel causing the latter to grind the bevel on the blade on a perfectlevel.

Fig. 1.

A plunger rod 35 extends upwardly from the plunger 32. A piston portion 36 is formed on the rod 35 above the plunger 32. A stop-pin 31 ex-' tends through the guide 33 between'the plunger I 32 and piston 36 to limit the vertical movement of the rod 35. A compression spring '38 is positioned in the guide 33 above-the-piston-36 and acts to constantly urge the plunger 32 downwardly; The length of the rod 35 is accurately formed so that its upper extremity will align perfectly with theqipper extremity of'theguide =33whenthe bottom-of'the'plunger 32 is in 'perfect alignment with the bottompf the frameblock-M; v inuse'ythe plunger is set over-the one extrem ity of the knife l 4; as shown in Fig" 1,- and l the knife is raised or lowered until the upper extremity'of thei rod-35 aligns perfectly 'with the upper extremityeof the holder 33.:- The plunger is then moved to the, other extremity of: the 'knifeanda similarfadjustment is made after-which the knife clampingrscrewsalfi aretightenedito lock the knife 'in'piacein'the head 13.; I

J It'isessentialthat the-path of theedgesof the lmives' be in exactali nment'with-the'top of the ream-table ll.- Thisalignmen-t is assured with thisidevice: since the upper extremity of the rod -35;will only align withthe upper extremity ofthe shown at'iilgso asto be above the generalplane of; the'bottom of the-block 20 so as not to be struckby the knives lar+ M. The guide 33 is preferably knurled as shown in to provide a convenient finger grip.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claim, without departing from the spirit of the invention.

vTHaving thusdescribed the invention, what is claimed and desired secured by Letters Patent is:

A device for use in sharpening jointer knives comprising: an elongated frame block; feet extending oppositely outward from the extremities of said'frame block, the bottom surface of said frame block and said feet being co-extensive; a forwardly and downwardly inclined forward surface on said frame block; an upwardly and forwardly extending projecting ledge extending longitudinally along the lower edge of said inclined surface at right angles thereto, there being a longitudinal -grooves-betweerr said ledge and-said inclined surface; a clamping bar extending along said inclined surface; a longitudinally extending flange along said clamping bar projecting into said groove; clamp screws extending through said clamping bar and into said frame block' for clamping said' clamping bar against a jointer knife lying on said inclined surface; and adjusting screws threadedv through said ledge, said screws lying in the plane of said jointer knife as; to contact the lower. edge thereof, said flange being'notched for the said passage of said screws.

, MAXWELL A. LORD.

REFERENCES CITED f 'Th'e following references are of 'recordhin the file of this patent: v w UNITED STATES PA s Number Name 7 Date 330,797 7 Mills Nov. 1'7, 1885 946,635 Franke Jan. v18, 1910 '1,21'4,241; Tuthill Jan. 30, 1917 1 22-.5,552 Wuesthofi May a, 1917 1,416,810 2 Foster May 23, 1922 Giampeter Feb. 14, 1923 

